In many commercial enterprises, sugar is utilized to a great extent for its sweetening properties. It is used in the sweetening of foods, for the manufacture of syrups and confectionery items, in preserves and jams, as a chemical intermediate for detergents, emulsifying agents and other sucrose derivatives such as plasticizers, resins, glues, etc. The usual derivation of sugar is from cane sugar and sugar beets. It is obtained by crushing and extracting the sugar from the cane with water or extracting the sugar from the sugar beet with water followed by evaporation and purifying with lime, absorbent carbon and/or various liquids. The chief component of this type of sugar is sucrose, while other sugars may contain other polysaccharides such as dextrose and levulose (fructose). Other polysaccharides which possess sweetening properties include glucose, maltose, etc. The various polysaccharides possess varying degrees of sweetness, especially when in pure form and not contaminated by an reversion products.
One source of glucose which possesses a relatively high degree of sweetness and which, in turn, may be converted to fructose, the latter possessing an even greater degree of sweetness, is a starch. As is well known, starch is present in many naturally occurring plants including corn, potatoes, rice, tapioca, wheat, etc. Heretofore, it has been known to treat starch with an enzyme such as amyloglucosidase to obtain glucose. However, the treatment heretofore provided entailed a relatively long residence time in order to obtain a glucose syrup which contained about 94% glucose. The relatively long residence time which has heretofore been required restricts the throughput of glucose and results in the appearance of reversion products which impart a bitter taste to the glucose, thus negating the sweetening property of the compound as well as requiring further treatment in order to remove the offending product. One such reversion product which imparts a bitter taste comprises isomaltose.
Many methods involving the use of an enzyme such as amyloglucosidase to convert starch into sugar have been tried. However, each of these methods has some disadvantages attached thereto. For example, when using a free enzyme, it is necessary to continuously replace the enzyme which is lost during the production of the desired saccharide. Likewise, when using an immobilized enzyme, the heretofore relatively long residence time has resulted in the appearance of unwanted side products.
As will hereinafter be shown in greater detail, we have now discovered that the feedstream comprising a starch which possesses a low dextrose equivalent may be subjected to a partial hydrolysis to provide a predetermined degree of conversion due to a correlation of residence time and liquid hourly space velocity, and to a degree wherein the reversion products which constitute an undesired side reaction are extremely low or, in some instances, non-existent.